This is a survey sent to the UKCRC registered clinical trials units asking about which central data monitoring they do and who does it within their clinical trials. We listed 16 central monitoring activities and asked about whether or not they were conducted on any, some or all trials and which staff role was responsible. The survey was sent out by the UKCRC in April2025 using MSForms.The survey questions are supplied in a 5 page Word file which also includes the introduction sent to potential participants. The anonymised data are supplied in an EXCEL file with 33 rows and 53 columns of data. There are 34 rows in the file as the first row is brief headings.